1. Field of the Invention
The present invention relates generally to a dual-shaft synchronous transmission fixing device, and more particularly to a fixing device having a main fixing plate and a subsidiary fixing plate, which are assembled with the transmission mechanism to securely fix the transmission mechanism for stably transmitting power.
2. Description of the Related Art
There are various electronic apparatuses provided with covers or display screens, such as mobile phones, notebooks, PDA, and electronic books. The covers or display screens are pivotally mounted on the electronic apparatuses via pivot pins or rotary shafts, whereby the covers or display screens can be freely rotated and opened/closed under external force.
In order to operate the display module (such as the screen) and/or the apparatus body module of the electronic apparatus in more operation modes and application ranges, a dual-shaft mechanism is provided between the display module and the apparatus body module, whereby the display module and/or the apparatus body module can be operated in different operation modes by different rotational angles. For example, U.S. Pat. No. 7,512,426 B2 discloses a mobile communications device with synchronizing hinge.
In general, the dual-shaft mechanism employs a complicated fixing structure assembled with multiple gaskets with through holes and recessed/raised locating sections, frictional plates and springs assembled on the rotary shafts. Two ends of the rotary shafts are respectively fixed by means of retainer rings or fixing members. The springs cooperatively store and release energy to rotate and locate the rotary shafts. Basically, according to the above structural design and assembling process, the assembling time cannot be shortened so that the manufacturing cost is increased.
There is also a conventional mechanism composed of rollers and drive wires (or transmission belts) for transmitting force to the rotary shaft so as to rotate the rotary shaft. As known by those who are skilled in this field, during the operation process of the wires or the transmission belts, delay of kinetic energy transmission will take place. This is because there is a gap between the wires (or transmission belts) and the rollers and the wires (or transmission belts) will slip or untruly operate. Also, the wires (or transmission belts) are made of elastic material and the fixing structure for assembling the wires (or transmission belts) with the rollers is not ideal. As a result, in force transmission, the load on the wires or the pulling force applied to the wires will increase. In this case, the transmission and shift effect of the wires will be deteriorated. Also, the force of the wires or transmission belts, which is preset in the initial assembling process will decrease due to elastic failure. Under such circumstance, the synchronous movement effect of the transmission mechanism will be deteriorated.
In order to improve the above problems, a conventional dual-shaft synchronous movement device has been developed. Such dual-shaft synchronous movement device employs multiple gears for transmitting force. However, as known by those who are skilled in this field, with the transmission gears, the gap between the shafts of the dual-shaft synchronous movement device can be hardly minified. Therefore, the entire transmission unit or structure will occupy a considerably large space. Especially, when the transmission unit is applied to a notebook or a miniaturized electronic device, the electronic device can hardly meet the requirement for lightweight and slimmed design. This is not what we expect.
The conventional rotary shaft structures and the relevant connection components thereof have some shortcomings in use and structural design that need to be overcome. It is therefore tried by the applicant to provide a dual-shaft synchronous movement device and an assembling method thereof to eliminate the shortcomings existing in the conventional rotary shaft structure so as to widen the application range and facilitate the assembling process of the rotary shaft structure. For example, in precondition of synchronous move and easy operation, a fixing device is provided to enhance the stability and fixing effect of the rotary shaft structures and the relevant connection components. In addition, the gap between the shafts can be changed or adjusted according to the transmission specification so as to minify the space occupied by the entire transmission unit or structure. Also, the components can be truly engaged with each other without the problems of slippage and delay of kinetic energy transmission. Accordingly, when the transmission unit is applied to an electronic device, the electronic device can meet the requirement for lightweight and slimmed design.